docs: def iter_ROOT_classes():
      """
      Iterator over all available ROOT classes
      """
      class_index = "http://root.cern.ch/root/html/ClassIndex.html"
      for s in minidom.parse(urlopen(class_index)).getElementsByTagName("span"):
          if ("class", "typename") in s.attributes.items():
              class_name = s.childNodes[0].nodeValue
              try:
                  yield getattr(QROOT, class_name)
              except AttributeError:
                  pass